1. Field of the Invention
This invention relates to acid-stable and cationic-compatible high surface area cellulose compositions that provide enhanced rheology and stability to suspensions, emulsions and foams, and their methods of preparation.
2. Background of the Invention
Sanitizers and disinfectants are a group of cleaning products used in hospital and institutional care, first aid facilities, and in food and agricultural hygiene. In general terms, sanitizers and disinfectants have some bacteriostatic or bacteriocidal properties. Sanitizers are used to reduce the number of living bacteria or viable viral particles on inanimate surfaces, or in water or air. Disinfectants destroy, or irreversibly inactivate bacteria, microbial fungi or viruses. Many of the compounds used as sanitizing and disinfecting agents are cationic surfactants, and many of the formulations used for cleaners, sanitizers and disinfectants are acidic. Typical cleaning additives, including cationic surfactants, form stable compositions, having good flow properties, when formulated in acidic or neutral media.
Cationic surfactants are used in a variety of other applications, for example, as emulsifiers, dispersants, or anti-caking agents. Cationic surfactants have also been used as de-bonding agents and have been added to cellulose pulps before drying to reduce the energy required to separate the dry pulp fibers for use as absorbants, U.S. Pat. No. 4,144,122.
Rheological modifiers or thickeners, such as xanthan and hydroxyethyl cellulose are often used in formulating sanitizers or disinfectants to enhance the aesthetic properties and to improve the ease of application and coating properties, for example, of hard surface cleaners. However, use of these modifiers or thickeners in stabilized sprayable foams and liquids, which remain on the surface upon application, is limited.
Cellulose, particularly reticulated bacterial cellulose has been used to prepare a variety of rheologically modified compositions. For example, U.S. Pat. No. 5,009,797 discloses a mixture of reticulated bacterial cellulose and a gellant, such as guar, hydroxypropyl guar, xanthan, hydroxyethyl cellulose, etc., for use in a high viscosity hydraulic fracturing fluid. U.S. Pat. No. 5,350,528 describes cross-linked fracturing fluids prepared using reticulated bacterial cellulose, a gellant and a cross-linking agent.
Water soluble polymers, such as cellulose derivatives, polyacrylamides or other polysaccharides have been used in combination with reticulated bacterial cellulose to prepare well bore drilling muds, useful for drilling subterranean formations, as disclosed in U.S. Pat. No. 5,362,713.
Non-aqueous, edible compositions of ultrahigh surface area cellulose have been disclosed in U.S. Pat. No. 5,366,750. These compositions were prepared by shearing co-dried mixtures of the cellulose and a chaotropic agent, particularly corn syrup, in a non-aqueous solvent.
However, the formation of stable, aqueous cellulose dispersions is pH dependent. Changing the pH of some of the cellulose compositions, described above, to either acidic or basic compositions, may result in flocculation and separation of the cellulose. The use of cellulose as a rheological modifier or stabilizer for suspensions, emulsions and foams requires the cellulose to form stable compositions, having high viscosity and good flow properties in the presence of cationic components and/or media having acidic or alkaline (basic) pH.
Accordingly, acid-stable and cationic-compatible cellulose compositions that are useful as rheological modifiers for cationic formulations, and particularly as rheological modifiers for sanitizer and disinfectant compositions, would be highly desirable.